Hmmm??? Well, since the computer in question is NOT MY computer, I can't afford any surprises of suddenly there being a Pterodactyl in the Ointment.
I'd feel much more comfortable engaging in this SP2 to SP3 updating stunt if it was MY computer. I wouldn't want to wind up in the situation of having destroyed their freshly-purchased computer. Especially after having made a BIG deal of my brother-in-law's scumball daughter having destroyed my Dell GX270 and me wanting to strangle her.
Anyway, so far neither my brother-in-law nor my sister have called to inform me of any problems with their computer's functionality.
So, in this case, it's probably best to play it safe and take the approach of --- Don't fix it if it ain't broke.
IF in the future they do start experiencing problems that can't be fixed by regular means, THEN I'll have to roll up my sleeves and engage in the SP2 to SP3 update. I'll of course inform them of the risk involved and that they can't hold me responsible if things get temporarily screwed up.